The present invention relates to a backplane type connector for connecting circuit boards electrically to each other, and to a method of producing the same.
Board-to-board connectors are widely used for connecting circuit boards to each other in order to increase the density of circuits or realizing a spatial arrangement of multiple circuit boards. These type of connectors generally include receptacle and plug connectors. The receptacle connector is mounted on a vertical circuit board, while the plug connector is mounted on a daughterboard. It is common for the surfaces of the daughterboards to be perpendicular to the surface of the backplane board, when the two connectors being mated together. Examples of the backplane type connector are disclosed in Japanese Patent Publication A-H06-013133 and U.S. Pat. No. 4,655,518
Recently, these backplane connectors have included multiple pin connectors in which the number of terminal pins ranges from several tens to several hundreds, and these are used in high-speed applications. These backplane connectors have the following problems.
The first problem relates to the electromagnetic shielding of the signal terminals. In some backplane connectors, the shield is only partly taken into account. For example, there exists a plug connector in which signal terminal pins are arranged in a plurality of rows and in a plurality of columns in the connector housing. Shield plates extend in the vertical direction at intervals in the housing width direction. As a result, cross-talk is generated between signal terminals between which there exists no shield plate.
The second problem is related to the manufacturability and production cost of the receptacle connector. There exists a receptacle connector equipped with a large number of contacts in which there are arranged in a lattice-like fashion, for example, 25 pins in the housing width direction and five pins in the housing thickness direction. In this receptacle connector, the large number of contacts are forced into attachment holes of the housing and attached thereto. In the process, the contacts and shield plates are alternately forced into the holes. Since the shield plates are forced in vertically, only five vertical rows of contacts can be forced in at one time. As a result, it is necessary to perform the contact-forcing-in process and the shield-plate-forcing-in process for every 25 times each, that is, for every 50 times in total, resulting in poor manufacturability and high production cost. Needless to say, the problem of the shield described above, is not solved in this case, either.
Japanese Patent Publication A-H07-114952 discloses a multi-polar electric connector in which shielding is possible not only between signal terminals of different rows but also between adjacent signal terminals of the same row. This technique is suitable for a relatively simple connector with a small number of poles. However, as the number of poles increases, the number of parts including shield plates, increases steeply, resulting in an increase in production cost due to the increase in assembly man-hour and the complication of the assembly operation. Further, the larger the number of poles is, the more complicated and the more delicate the housing becomes, which leads to a problem related to formability and a problem related to the manufacturability of the mold.